The present invention relates to an inspection method and apparatus for a semiconductor integrated circuit (to be referred to as a "chip" hereinafter) formed on a semiconductor wafer (to be referred to as a "wafer" hereinafter), and a vacuum contactor that can be used by them.
A semiconductor manufacturing process includes the step of inspecting a large number of chips formed on a wafer before dicing. As an inspection apparatus for inspecting the chips on the wafer one by one or a plurality of chips on the wafer in a batch, a probe apparatus is widely used. This probe apparatus generally has a wafer convey mechanism, a sub-chuck, a main chuck, a probe card, a connection ring, a performance board, and a test head. The wafer convey mechanism conveys the wafer one by one. The sub-chuck pre-aligns the wafer with reference to the orientation flat while the wafer is being conveyed by the wafer convey mechanism. The main chuck is movable in the X, Y, Z, and .theta. directions and receives the pre-aligned wafer through the convey mechanism. The probe card is arranged above the main chuck. The connection ring electrically connects the probe card and a tester to each other.
Inspection of the electrical characteristics of the wafer is performed by the step of moving the main chuck having the wafer placed thereon in the X, Y, Z, and .theta. directions to align the electrodes on the chips of the wafer and the measuring contacts (e.g., probe pins) of the probe card with each other, the step of over-driving the main chuck in the Z direction to bring the electrodes of the wafer into electrical contact with the probe pins, and the step of inspecting the electrical characteristics of the respective chips based on inspection signals output from the probe pins while the probe pins and the electrodes are in contact with each other.
Recently, as the integration degree of the semiconductor integrated circuits has advanced sharply, the number of electrodes has increased, and the number of probe pins that are brought into contact with the electrodes has become as large as 2,000. To achieve conduction between the electrodes and the probe pins, for example, a pressure of 5 g is applied to each probe pin. When the number of probe pins reaches as large as 2,000, as described above, the total pressure applied to all the probe pins becomes about 10 kg. The main chuck must be able to apply this pressure to the probe pins. When the main chuck applies this pressure, a local pressure (local load) acts on the main chuck to incline it albeit slightly. Then, because of size reduction of the electrodes as well, at least some probe pins are dislodged from the electrode positions to degrade the inspection precision.
In the conventional contactor method wherein the main chuck is over-driven in the Z direction to bring the probe pins and the electrode pads into tight contact with each other, since it is difficult to eliminate this local load itself, a measure must be taken for the local load of the main chuck. If, for example, the rigidity of the main chuck is increased as a measure against the local load, the main chuck and the like become more and more heavy, and the cost increases.